As one of the medical instruments for treating cardiac disease, a heart correction net that is fitted to the outside of a heart has been proposed (see, for example, Patent Document 1). This heart correction net is formed with a mesh-structured fabric into a cup-like shape. Such heart correction net is fitted to the outside of a heart of a patient with cardiac failure in order to inhibit further cardiac dilatation (cardiac remodeling) and to prevent deterioration of cardiac failure.
In case of the heart correction net disclosed in Patent Document 1, the net is configured based on the size of a relatively large heart so that the net can be fitted to a heart irrespective of the size thereof. Due to such configuration, an excess portion of the net needs to be removed while in surgery according to the size of the patient's heart, and, subsequently, the portion from which the excess portion is removed needs to be sutured.
Meanwhile, if the removal amount of the excess portion is insufficient, the heart correction net may become too large for the heart. In this case, the effect to inhibit cardiac dilatation becomes deficient. On the other hand, if the removal amount is unnecessarily large, the heart correction net may become too small for the heart, which may cause diastolic dysfunction. Therefore, the removal amount has to be appropriately determined. However, since no standard has been available regarding the removal amount, decisions have been left to surgeons' subjective views. This has been causing variation in treatment results. Moreover, removal and suture procedures require time, which places a burden on patients as much as the length of the time the procedures take.
In order to solve these problems, the inventors of the present case have proposed a technique, in which patients' hearts that are individually different in sizes and shapes are actually three-dimensionally measured, and heart correction nets are knitted so as to have the configurations that snugly conform to patients respectively (see Patent Document 2). In this technique, with a tomographic apparatus, such as CT (Computed Tomography), an MRI (Magnetic Resonance Imaging), and an echocardiographic apparatus, cross-sectional images of a heart are measured. A contour of the heart (two-dimensional data) is extracted from each of the cross-sectional images. Based on the contours from the plurality of the cross-sectional images, three-dimensional data is created. Paper-pattern data, created based on the three-dimensional data, is inputted into a computerized knitting machine that is capable of multidimensional knitting. As a result, a heart correction net is produced so as to snugly conform to a patient's heart.
The heart correction net, manufactured with such technique, is fitted to a heart only by covering. Unlike a large general-purpose heart correction net, an unnecessary portion of the net does not have to be removed in a surgery in order to adjust the heart correction net to the size of a patient's heart. Therefore, surgery can be performed faster for not removing the unnecessary portion, which can considerably shorten surgical time and reduce the burden on patients.